The present invention relates to an apparatus for manufacturing a core for a rotational electric machine such as a stator core or a rotor core for a motor. Specifically, the invention relates to a rotary lamination apparatus for rotating and laminating core pieces punched from a thin plate.
This type of rotary lamination apparatus is described in, for example, Japanese Laid-Open Patent Publication No. 2003-19520. FIG. 6 shows a typical configuration of conventional rotary lamination apparatuses, including the apparatus described in this publication.
In this rotary lamination apparatus, a thin plate material W is mounted on a die 104. A punch 108 is then lowered into the inner space formed by the die 104 to punch a core piece Wa from the thin plate material W. Punched core pieces Wa are pressed and held by a pressing ring 105 from the outer circumference and mounted on a mounting table 106. Each time a single core piece or a predetermined number of core pieces Wa are punched, a holding member 103 and the die 104 are each rotated by a predetermined angle. Thus, the punched core pieces Wa are rotated relative to cores WA, which have been already laminated, and mounted on the cores WA. In this manner, rotary lamination is carried out.
With reference to FIGS. 7 and 8, each of the core pieces Wa includes a plurality of positioning portions Pa, which project in one direction. Corresponding positioning portions Pa are engaged with one another to maintain the core WA in a laminated state.
By rotating and laminating punched core pieces to form a core in the above-described manner, variation in the thickness among the punched core pieces is canceled.